Two-part accommodating intraocular lens device

ABSTRACT

A two-part accommodating intraocular lens (IOL) device for implantation in a capsular bag of a patient&#39;s eye. The IOL device includes a primary lens assembly and a power changing lens. The primary lens assembly includes a fixed lens and a peripherally disposed centration member. The centration member has a circumferential distal edge and a first coupling surface adjacent the circumferential distal edge. The power changing lens has an enclosed, fluid- or gel-filled lens cavity and haptic system disposed peripherally of the lens cavity. The haptic system has a peripheral engaging edge configured to contact the capsular bag and a second coupling surface. The first and second coupling surfaces are in sliding contact with one another to permit movement of the power changing lens relative to the primary lens assembly and also to maintain a spaced relationship between the fixed lens and the lens cavity during radial compression of the power changing lens.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/US2014/063538 filed Oct. 31, 2014, which claims the benefit ofProvisional Patent Application No. 61/899,110 filed Nov. 1, 2013, bothof which are incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates generally to an accommodating intraocular lensdevice and, more particularly, to an accommodating intraocular lensdevice configured for implantation in a lens capsule of a subject's eye.

BACKGROUND

Surgical procedures on the eye have been on the rise as technologicaladvances permit for sophisticated interventions to address a widevariety of ophthalmic conditions. Patient acceptance has increased overthe last twenty years as such procedures have proven to be generallysafe and to produce results that significantly improve patient qualityof life.

Cataract surgery remains one of the most common surgical procedures,with over 16 million cataract procedures being performed worldwide. Itis expected that this number will continue to increase as average lifeexpectancies continue to rise. Cataracts are typically treated byremoving the crystalline lens from the eye and implanting an intraocularlens (“IOL”) in its place. As conventional IOL devices are primarilyfocused for distance visions, they fail to correct for presbyopia andreading glasses are still required. Thus, while patients who undergo astandard IOL implantation no longer experience clouding from cataracts,they are unable to accommodate, or change focus from near to far, fromfar to near, and to distances in between.

Surgeries to correct refractive errors of the eye have also becomeextremely common, of which LASIK enjoys substantial popularity with over700,000 procedures being performed per year. Given the high prevalenceof refractive errors and the relative safety and effectiveness of thisprocedure, more and more people are expected to turn to LASIK or othersurgical procedures over conventional eyeglasses or contact lens.Despite the success of LASIK in treating myopia, there remains an unmetneed for an effective surgical intervention to correct for presbyopia,which cannot be treated by conventional LASIK procedures.

As nearly every cataract patient also suffers from presbyopia, there isconvergence of market demands for the treatment of both theseconditions. While there is a general acceptance among physicians andpatients of having implantable intraocular lens in the treatment ofcataracts, similar procedures to correct for presbyopia represent only5% of the U.S. cataract market. There is therefore a need to addressboth ophthalmic cataracts and/or presbyopia in the growing agingpopulation.

BRIEF SUMMARY

The two-part accommodating IOL devices disclosed herein provides for anumber of advantages owing to its separate two-part construction.Implantation of the IOL device requires a significantly reduced incisionsize, as the two parts of the IOL device are implanted separately andthus significantly reducing the delivery profile for implantation. Thereduced incision size provides for a number of advantages, includingobviating the need for anesthesia and sutures to close the incision siteand improved surgical outcomes.

Additionally, greater control is afforded with respect to adjusting thesizing and the power of the IOL during surgery. Implanting the primarylens into the lens capsule will provide the physician an impression asto the size of the patient's lens capsule and will thus help verify thecorrect size of the power changing lens that will subsequently beimplanted.

In one embodiment, a two-part accommodating intraocular lens (IOL)device for implantation in a capsular bag of a patient's eye isdescribed. The IOL device comprises a primary lens assembly and a powerchanging lens assembly. The primary lens assembly comprises a fixed lensand a centration member disposed peripherally of the fixed lens. Thecentration member has a circumferential distal edge and a first couplingsurface adjacent the circumferential distal edge. The power changinglens comprises an enclosed and fluid- or gel-filled lens cavity and ahaptic system disposed peripherally of the lens cavity. The hapticsystem has a peripheral engaging edge configured to contact the capsularbag and a second coupling surface facing the first coupling surface andlocated adjacent the peripheral engaging edge. The first and secondcoupling surfaces are in sliding contact with one another to permitmovement of the power changing lens relative to the primary lensassembly. The first and second coupling surfaces maintain a spacedrelationship between the fixed lens and the lens cavity when the powerchanging lens is radially compressed.

In accordance with a first aspect, a diameter d₁ of the power changinglens is greater than a diameter d₂ of the primary lens assembly in theabsence of radial compression.

In accordance with a second aspect, the fixed lens does not change shapeor curvature during accommodation.

In accordance with a third aspect, the lens cavity changes both shapeand curvature during accommodation.

In accordance with a fourth aspect, the fixed lens and the lens cavityare positive power lenses.

In accordance with a fifth aspect, the fluid- or gel-filled lens cavityis a biconvex lens.

In accordance with a sixth aspect, the fixed lens assembly comprises asquared edge located circumferentially around the fixed lens outside ofthe optical zone.

In accordance with a seventh aspect, the facing surfaces of thecentration member and the haptic system each comprise one of acomplementary and interlocking pair, the interlocking pair beingdisposed circumferentially around the fixed lens and the power changinglens, respectively.

In accordance with an eighth aspect, the peripheral engaging edge isthicker than the circumferential distal edge.

In accordance with a ninth aspect, the thickness ratio of thecircumferential distal edge to the peripheral engaging edge is in therange of about 1:5 to about 1:2.

In accordance with a tenth aspect, the primary lens assembly has ahigher Young's modulus of elasticity than the power changing lens.

In accordance with an eleventh aspect, at least one of the centrationmember and the haptic system comprises a plurality of openings.

In accordance with a twelfth aspect, the power changing lens iscomprised of two opposing surfaces which are displaced away from eachother upon the application of a radial force along a peripheral edge,the two opposing surfaces having central and peripheral regions and agradually increasing thickness profile from the peripheral to thecentral regions.

In another embodiment, a two-part accommodating intraocular lens (IOL)device for implantation in a capsular bag of a patient's eye isdescribed. The IOL comprises a primary lens assembly and a powerchanging lens assembly. The primary lens assembly comprises a fixed lensand a centration member disposed peripherally of the fixed lens. Thecentration member has a radially-compressible peripheral edge having anouter circumferential surface configured to engage the capsular bag ofthe patient's eye and an inner circumferential surface spaced radiallyinward of the outer circumferential surface. The power changing lenscomprises an enclosed and fluid- or gel-filled lens cavity and a hapticsystem disposed peripherally of the lens cavity. The haptic system has acircumferential edge configured to engage the inner circumferentialsurface. Radial compression applied to the outer circumferential surfacecauses at least one of an increase in curvature and a decrease indiameter of the lens cavity and radial compression applied to the outercircumferential surface does not cause an increase in curvature or adecrease in diameter of the fixed lens.

In accordance with a first aspect, the centration member furthercomprises circumferential hinges between the fixed lens and theperipheral edge, the circumferential hinges being disposed on opposingsides of the centration member.

In accordance with a second aspect, the centration member furthercomprises a single circumferential hinge between the fixed lens and theperipheral edge.

In accordance with a third aspect, the circumferential hinge is disposedon an inner surface of the haptic facing the power changing lens.

In accordance with a fourth aspect, the circumferential edge of thehaptic system and the inner circumferential surface of the peripheraledge have complementary rounded surfaces and radial compression appliedto the outer circumferential surface cause the peripheral edge to tiltradially inwardly about the circumferential hinge.

In accordance with a fifth aspect, the power changing lens is entirelycontained within the peripheral edge of the primary lens assembly.

In accordance with a sixth aspect, the power changing lens furthercomprises a circumferential lip disposed radially inwardly of the innersurface of the circumferential edge.

In accordance with an seventh aspect, the power changing lens iscomprised of two opposing surfaces which are displaced away from eachother upon the application of a radial force along a peripheral edge,the two opposing surfaces having central and peripheral regions, whereinthe region has a thickness that is at least two times, preferably atleast three times, and most preferably at least 4 times greater than athickness of the peripheral region.

In a further embodiment, a method for implanting a two-part IOL devicein a capsular bag of a patient's eye is described. The method comprisesfirst inserting and positioning a primary lens assembly in the capsularbag of the patient's eye through an incision located in the cornea, theprimary lens having a fixed lens and a centration member disposedperipherally of the fixed lens. The next step comprises inserting andpositioning a power changing lens in the capsular bag of the patient'seye anteriorly of the primary lens assembly, the power changing lenscomprising an enclosed and fluid- or gel-filled lens cavity and a hapticsystem disposed peripherally of the lens cavity, the haptic systemhaving a peripheral engaging edge configured to contact the capsularbag. The primary lens assembly is in contact with a posterior portion ofthe capsular bag and the power changing lens is in contact with theanterior portion of the capsular bag after implantation. The fixed lensand the lens cavity are centered about an optical axis.

In accordance with a first aspect, the incision is less than 5 mm,preferably less than 4 mm, and most preferably less than 3 mm.

In accordance with a second aspect, both of the inserting steps areperformed through the incision.

In accordance with a third aspect, the method further comprisesinjecting a viscoelastic material before the inserting and positioningof the power changing lens.

Other objects, features and advantages of the described preferredembodiments will become apparent to those skilled in the art from thefollowing detailed description. It is to be understood, however, thatthe detailed description and specific examples, while indicatingpreferred embodiments of the present invention, are given by way ofillustration and not limitation. Many changes and modifications withinthe scope of the present invention may be made without departing fromthe spirit thereof, and the invention includes all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative embodiments of the present disclosure are described hereinwith reference to the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of an embodiment of the two-partaccommodating IOL.

FIG. 2 is an exploded side cross-sectional view of the two-partaccommodating IOL of FIG. 1.

FIG. 3 is an assembled side view of the two-part accommodating IOL ofFIG. 1, in which the power changing lens and the primary lens are insliding contact with one another.

FIG. 4A through 4F are a cross-sectional view of various embodiments ofthe two-part accommodating IOL.

FIG. 5 is an exploded perspective view of an embodiment of the two-partaccommodating IOL.

FIGS. 6A and 6B are a top and side plan views of the power-changing lensof the two-part IOL of FIG. 5.

FIGS. 7A and 7B are top and side plan views of the primary lens of thetwo-part IOL of FIG. 5.

FIGS. 8A and 8B are exploded and coupled cross-sectional views ofanother embodiment of a two-part accommodating IOL in which the powerchanging lens and the primary lens are coupled together.

FIGS. 9A and 9B are cross-sectional views of alternate embodiments of atwo-part accommodating IOL in which the power changing lens and theprimary lens are coupled together.

FIGS. 10A and 10B are exploded and coupled cross-sectional views of afurther embodiment of a two-part accommodating IOL in which the powerchanging lens and the primary lens are coupled together.

FIGS. 11A through 11F are top views of various alternate embodiments ofthe primary lens.

Like numerals refer to like parts throughout the several views of thedrawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Specific, non-limiting embodiments of the present invention will now bedescribed with reference to the drawings. It should be understood thatsuch embodiments are by way of example and are merely illustrative ofbut a small number of embodiments within the scope of the presentinvention. Various changes and modifications obvious to one skilled inthe art to which the present invention pertains are deemed to be withinthe spirit, scope and contemplation of the present invention as furtherdefined in the appended claims.

FIGS. 1-3 depict an embodiment of a two-part accommodating IOL device100 in which the power changing lens 110 and the primary lens 120 are insliding contact with one another.

The power changing lens 110 is depicted as comprising a fluid- orgel-filled lens chamber 112 and a haptic system 114 disposedperipherally of the fluid- or gel-filled lens chamber 112. The hapticsystem 114 comprises a peripheral engaging edge 116 that is configuredto engage the capsular bag of the patient's eye, generally at a locationwhere it is attached via zonules to the ciliary muscles. A plurality ofthrough holes 115 may be disposed along the circumference of the hapticsystem 114 to reduce material bulk and thus the delivery profile of thepower changing lens 110.

The primary lens 120 is depicted as comprising a fixed-power lens 122and a plurality of centration members 124 disposed symmetrically aboutthe fixed-power lens. The centration member 124 comprises a distal edge126 and through holes 125 to reduce the resistance to radial compressionexerted by the capsular bag.

The presence of the holes 115 in the power lens 110 allows themanipulation of both the power lens 110 and the primary lens 120underneath it. The holes 115 also help reduce the delivery profile ofthe power lens 110 and permits both the power lens 110 and the primarylens 120 to be manipulated to center it in the capsular bag duringimplantation. The presence of holes 115 may also reduce the rigidity ofthe power lens. Similarly, the primary lens 120 also has holes 125 thatpermit manipulation and reduce delivery profile. The holes 125 of theprimary lens 120 are additionally shaped so as to reduce the likelihoodof grabbing the power changing lens 110 when the power changing lens 110is implanted into the capsular bag of the patient's eye after theprimary lens 120 has already been implanted.

The power changing lens 110 and the primary lens 120 is configured to bein sliding contact with one another, while maintaining a separationbetween the fluid- or gel-filled lens chamber 112 and the fixed-powerlens 122. In one embodiment, this distance is maintained by anglingeither one or both of the haptic system 114 and the centration member124 towards one another. As shown in FIGS. 2 and 3, the sliding contactbetween the power changing lens 110 and the primary lens 120 is made atthe first and second coupling surfaces 118, 128, respectively.

The power changing lens 110 is sized and shaped to take on and respondto the radially-inward forces which are applied along the peripheraledge 116 of the lens 110. In contrast, the primary lens 120 does notparticipate in providing an accommodative response and thus is sized andshaped so as to avoid interfering or resisting the radial compressiveforces that are applied to the power changing lens 110. This may beaccomplished by controlling the relative diameters and thicknesses ofthe power changing lens 110 and the primary lens 120 to maximize theextent to which the radial compressive forces are applied onto the powerchanging lens 110 and to minimize the extent to which these forces areapplied onto the primary lens 120.

In a preferred embodiment, as depicted in FIG. 2, the thickness t₁ ofperipheral engaging edge 116 of the power changing lens 110 issubstantially thicker than the thickness t₂ of the distal edge 126 ofthe fixed-power lens 122. In a preferred embodiment, the thickness ratioof t₁ to t₂is 2:1, preferably 3:1, more preferably 4:1 and mostpreferably 5:1. In another preferred embodiment, as depicted in FIG. 3,the diameter d₁ of the power changing lens 110 is greater than thediameter d₂ of the primary lens 120.

In one preferred embodiment, at least the opposing sides or walls of thelens chamber 112 is made of a material of sufficient mechanical strengthto withstand physical manipulation during implantation, but is ofsufficiently low Young's modulus so as to minimize its resistance todeformation. In a preferred embodiment, the opposing sides of the lenschamber 112 is made of a polymer having a Young's modulus of 100 psi orless, preferably 75 psi or less, and most preferably 50 psi or less. Inone preferred embodiment, the remaining portions of the IOL 100 has aYoung's modulus that is greater than the Young's modulus of the lenschamber 112. The walls of the lens chamber 112 may be a polymer,preferably a silicone polymer and more preferably a phenyl siloxane,such as a vinyl-terminated phenyl siloxane or a vinyl-terminateddiphenyl siloxane. In order to impart sufficient mechanical strength,the polymer may be crosslinked, reinforced with fillers, or both. Thefillers may be a resin or silica that have been functionalized to reactwith the polymer.

The walls of the lens chamber 112 define an enclosed cavity that isfilled with a fluid or gel having specific physical and chemicalcharacteristics to enhance the range of refractive power provided by theIOL during accommodation. The fluid or gel is selected such that itcooperates with the power changing lens 110 in providing a sufficientrange of accommodation of up to at least 3 diopters, preferably up to atleast 5 diopters, preferably up to at least 10 diopters and mostpreferably up to at least 15 diopters. In a preferred embodiment, theenclosed cavity is filled with the fluid or gel before implantation ofthe IOL 100 into the capsular bag 40 of the eye and, in a more preferredembodiment, the cavity is filled with the fluid or gel in themanufacture of the IOL 100.

FIGS. 4A-4F and 8-10 more clearly depict the location of the fluid orgel (213, 313, 413, 513) contained within the power changing lens (210,310, 410, 510). In one preferred embodiment the enclosed cavity definedby the walls of the lens chamber 112 is filled with a fluid, such as agas or a liquid, having low viscosity at room temperature and a highrefractive index. In a preferred embodiment, the fluid (213, 313, 413,513) is a liquid having a viscosity of 1,000 cP or less at 23° C. and arefractive index of at least 1.46, 1.47, 1.48, or 1.49. The fluid may bea polymer, preferably a silicone polymer, and more preferably a phenylsiloxane polymer, such as a vinyl-terminated phenyl siloxane polymer ora vinyl-terminated diphenyl siloxane polymer. Preferably in embodimentswhere the fluid is made of a polymer, the polymer is preferably notcrosslinked and the polymer may be linear or branched. Where the fluidis a vinyl-terminated phenyl siloxane polymer or diphenyl siloxanepolymer, the vinyl groups may be reacted to form other moieties that donot form crosslinkages.

In accordance with one embodiment, fluid (213, 313, 413, 513) may be apolyphenyl ether (“PPE”), as described in U.S. Pat. No. 7,256,943,entitled “Variable Focus Liquid-Filled Lens Using Polyphenyl Ethers” toTeledyne Licensing, LLC, the entire contents of which are incorporatedherein by reference as if set forth fully herein.

In accordance with another embodiment, the fluid (213, 313, 413, 513)may be a fluorinated polyphenyl ether (“FPPE”). FPPE has the uniqueadvantage of providing tunability of the refractive index while being achemically inert, biocompatible fluid with dispersion properties. Thetunability is provided by the increasing or decreasing the phenyl andfluoro content of the polymer. Increasing the phenyl content willeffectively increase the refractive index of the FPPE, whereasincreasing the fluoro content will decrease the refractive index of theFPPE while decreasing the permeability of the FPPE fluid through thewalls of the lens chamber 112.

In another preferred embodiment, the enclosed cavity defined by walls ofthe lens chamber 112 is filled with a gel (213, 313, 413, 513). The gel(213, 313, 413, 513) preferably has a refractive index of at least 1.46,1.47, 1.48, or 1.49. The gel may also preferably have a Young's modulusof 20 psi or less, 10 psi or less, 4 psi or less, 1 psi or less, 0.5 psior less, 0.25 psi or less and 0.01 psi or less. In a preferredembodiment, the gel (213, 313, 413, 513) is a crosslinked polymer,preferably a crosslinked silicone polymer, and more preferably acrosslinked phenyl siloxane polymer, such as a vinyl-terminated phenylsiloxane polymer or a vinyl-terminated diphenyl siloxane polymer. Otheroptically clear polymer liquids or gels, in addition to siloxanepolymers, may be used to fill the enclosed cavity and such polymers maybe branched, unbranched, crosslinked or uncrosslinked or any combinationof the foregoing.

A gel has the advantages of being extended in molecular weight frombeing crosslinked, more self-adherent and also adherent to the walls oropposing sides lens chamber 112 than most liquids. This makes a gel lesslikely to leak through the walls of the power changing lens. In order toobtain the combination of accommodative power with relatively smalldeformations in the curvature of the power changing lens, the gel (213,313, 413, 513) is selected so as to have a high refractive index whilebeing made of an optically clear material that is characterized ashaving a low Young's modulus. Thus, in a preferred embodiment, the gelhas a refractive index of 1.46 or greater, preferably 1.47 or greater,1.48 or greater and most preferably 1.49 or greater. At the same time,the gel preferably has a Young's modulus of 10 psi or less, preferably 5psi or less, and more preferably 1 psi or less. In a particularlypreferred embodiment, the gel has a Young's modulus of 0.5 psi or less,preferably 0.25 psi or less, and most preferably 0.01 psi or less. It isunderstood that at lower Young's modulus, the gel will present lessresistance to deformation and thus the greater the deformation of thepower changing lens 110 for a given unit of applied force.

In particularly preferred embodiment, the gel is a vinyl-terminatedphenyl siloxane that is produced based on one of the four formulasprovided as follows:

Formula 1:

-   -   100 parts 20-25 mole % vinyl terminated        diphenylsiloxane-dimethylsiloxane copolymer (Gelest PDV 2335).    -   3 ppm platinum complex catalyst    -   0.35 pph of phenyl siloxane hydride crosslinker (Nusil XL-106)    -   Young's modulus of elasticity=0.0033 psi

Formula 2:

-   -   100 parts 20-25 mole % vinyl terminated        diphenylsiloxane-dimethylsiloxane copolymer (Gelest PDV 2335).    -   3 ppm platinum complex catalyst    -   0.4 pph of phenyl siloxane hydride crosslinker (Nusil XL-106)    -   Young's modulus of elasticity=0.0086 psi

Formula 3:

-   -   100 parts 20-25 mole % vinyl terminated        diphenylsiloxane-dimethylsiloxane copolymer (Gelest PDV 2335).    -   3 ppm platinum complex catalyst    -   0.5 pph of phenyl siloxane hydride crosslinker (Nusil XL-106)    -   Young's modulus of elasticity=0.0840 psi

Formula 4:

-   -   100 parts 20-25 mole % vinyl terminated        diphenylsiloxane-dimethylsiloxane copolymer (Gelest PDV 2335).    -   3 ppm platinum complex catalyst    -   0.6 pph of phenyl siloxane hydride crosslinker (Nusil XL-106)    -   Young's modulus of elasticity=2.6 psi

The walls of the lens chamber and the fluid or gel contained within thecavity is preferably selected so as to prevent or reduce the likelihoodof the fluid or gel migrating outside of the lens chamber. Thus, in apreferred embodiment, one or both of the power changing lens and thefluid or gel (213, 313, 413, 513) is/are selected from biocompatiblematerials that optimize the resistance to permeability of the fluid orgel across the power changing lens.

One method of decreasing the permeability of the gel contained insidethe cavity and across the power changing lens is to provide a gel thatis cross-linked. The degree of cross-linking, however, must be selectedand controlled such that, on the one hand, the power changing lens andthe gel have a sufficiently low Young's modulus to minimize theresistance of the power changing lens to deformation and, on the otherhand, to minimize the permeation of the gel across the power changinglens. Thus, in a preferred embodiment, longer chain polymers that arelightly cross-linked, such as those used for silicone gels, startingwith monomers having molecular weights that are greater than 35,000daltons, preferably greater than 50,000 daltons and, most preferably, atleast 70,000 daltons are desired.

In another preferred embodiment, a gel is used having low permeabilityextractables. Such gels may be formulated by using long chain polymersthat are branched.

In a preferred embodiment, one or both of the lens chamber walls and thegel may be made of homo- or co-polymers of phenyl-substituted silicones.

For the lens chamber walls, the crosslinked homo- or co-polymerspreferably have a diphenyl content of 5-25 mol %, preferably 10-20 mol %and more preferably 15-18 mol %. Alternatively, for the lens chamberwalls, the homo- or co-polymers preferably have a phenyl content of10-50 mol %, preferably 20-40 mol %, and more preferably 30-36 mol %.

For the gel, the homo- or co-polymers preferably have a diphenyl contentof 10-35 mol %, preferably 15-30 mol % and more preferably 20-25 mol %.Alternatively, for the gel, the homo- or co-polymers preferably have aphenyl content of 20-70 mol %, preferably 30-60 mol % and morepreferably 40-50 mol %.

In a particularly preferred embodiment, the walls of the lens chamberare made of a crosslinked phenyl siloxane having a diphenyl content ofabout 15-18 mol % or a phenyl content of about 30-36 mol % and the gelis made of a phenyl siloxane having a diphenyl content of about 20-25mol % or a phenyl content of about 40-50 mol %. The walls of the lenschamber walls are understood to be more crosslinked than the gel.

In a particularly preferred embodiment, the lens chamber walls are madeof a vinyl-terminated phenyl siloxane, most preferably a crosslinkedvinyl-terminated phenyl siloxane. Reinforcing agents, such as silica,may also be included in a range of 10-70 mol %, preferably 20-60 mol %and most preferably 30-50 mol %.

The walls of the lens chamber and the fluid or gel contained within thecavity is also preferably selected so as to increase the range ofaccommodative power that is provided by the lens chamber. In onepreferred embodiment, the walls of the lens chamber are made of amaterial having a lower refractive index than the fluid or gel containedin the enclosed cavity. In one preferred embodiment, the refractiveindex of the walls of the lens chamber is 1.38 and the refractive indexof the gel or fluid contained therein is 1.49.

The differential refractive indices provided by the lens chamber wallsand the gel or liquid contained within the lens chamber may be providedby differences in the materials or the composition of the materials usedfor the lens chamber walls and the gel or liquid.

In one embodiment, both the lens chamber walls and the gel or liquid ismade of a phenyl siloxane having different diphenyl or phenyl content.In a preferred embodiment, the lens chamber walls have a diphenyl orphenyl content that is less than that for the gel or liquid. In anotherpreferred embodiment, the walls of the lens chamber may be made of across-linked vinyl-terminated phenyl siloxane having a diphenyl contentof about 15-18 mol % or a phenyl content of about 30-36 mol % and thegel contained within the lens chamber walls may be made of avinyl-terminated phenyl-siloxane having a diphenyl content of 20-25 mol% or a phenyl content of 30-36 mol %.

In another embodiment, the differential refractive indices may beprovided by providing a dimethyl siloxane for the lens chamber walls andthe gel may be a phenyl siloxane having a high diphenyl or phenylcontent. In a preferred embodiment, the diphenyl content is at last 20mol %, at least 25 mol %, at least 30 mol %, at least 35 mol %, and atleast 40 mol %. Alternatively, the phenyl content is at least 40 mol %,at least 50 mol %, at least 60 mol %, at least 70 mol % and at least 80mol %.

In a further embodiment, the differential refractive indices may beprovided by a crosslinked fluoro siloxane, such as a3,3,3-trifluoropropylmethyl siloxane and the gel may be a phenylsiloxane having a high diphenyl or phenyl content. In a preferredembodiment, the diphenyl content is at least 20 mol %, at least 25 mol%, at least 30 mol %, at least 35 mol %, and at least 40 mol %.Alternatively, the phenyl content is at least 40 mol %, at least 50 mol%, at least 60 mol %, at least 70 mol %, and at least 80 mol %.

FIGS. 4A-4F depict alternate embodiments of the two-part IOL device200A-F in which the shape and configuration of the power changing lens210 and the primary lens 230 are varied.

In each of these embodiments, certain features remain the same. Thepower changing lens 210 is depicted as comprising a fluid- or gel-filledlens chamber 212 and a haptic system 214 disposed peripherally of thefluid- or gel-filled lens chamber 212. The lens chamber 212 comprisestwo opposing surfaces which are divided into a central regions 212 a,212 b about the central axis A-A (See FIG. 1) and peripheral regions 211a, 211 b. In a preferred embodiment, the central regions 212 a, 212 bhave a gradually increasing thickness radially towards the center of thelens chamber 212 from the peripheral regions 211 a, 211 b.

In a preferred embodiment, the center point of the central regions 212a, 212 b has a thickness that is two times or more, preferably threetimes or more, and most preferably 4 times or more than the thickness ofthe peripheral region 211 a, 211 b. A fluid or gel 213 is containedbetween the opposing surfaces. In another preferred embodiment, thepoint of greatest thickness in the central region 212 a, 212 b and thepoint of least thickness in the peripheral region 211 a, 211 b is aratio of 2:1 or greater, preferably 3:1 or greater, and most preferably4:1 or greater. In a preferred embodiment, the thickness at the opticalaxis or the center of the central region 212 a, 212 b is about 200microns and the thickness at the peripheral region 211 a, 211 b is about50 microns. The increased thickness in the central region 212 a, 212 bis provided so as to prevent the opposing surfaces of the lens chamber212 from buckling when it is deformed in response to accommodation. Itis understood that in the various embodiments of the power lens depictedin the figures, the opposing sides preferably has the thickness profilesas described herein and depicted in FIGS. 4A-4F. References to theoptical axis or optical axis A-A made herein is understood to mean theline bisecting the center of the IOL device, as shown in FIG. 1.

The opposing surfaces of the lens chamber 212 actuate towards and awayfrom each other when the eye is unaccommodated and accommodated,respectively. The haptic system 214 comprises a peripheral engaging edge216 and a first coupling surface 218 adjacent the peripheral engagingedge 216. The primary lens assembly 230 comprises a fixed lens 232 and aplurality of centration members 224 disposed about the fixed lens 232.The centration members 224 comprise a distal edge 236 and a secondcontacting surfaces 238 in sliding contact with the first contactingsurfaces 218 of the power changing lens 210.

In a preferred embodiment, the primary lens 230 is substantially thickerthan one of the opposing sides lens chamber 212, as measured along theoptical axis A-A. In a preferred embodiment, the thickness of each oneof the opposing sides lens chamber 212, as along the optical axis A-A isless than ½, preferably less than ⅓, preferably less than ¼, and mostpreferably less than ⅕ of the thickness of the primary lens 230 at thecentral optical axis A-A. Because the primary lens 230 is substantiallythicker than either one of the opposing sides lens chamber 212, theprimary lens 230 has an effective Young's modulus that is substantiallygreater than either one of the opposing sides of the chamber 212.

Turning now to the various distinguishing features of the two-part IOLdevices, reference is made with respect to FIG. 4A of the IOL device200A in which the primary lens 230 is depicted as comprising a hinge 240and angled or squared edge 239. The hinge 240 is provided on thecentration members 224 to permit it to bend axially, compress radially,or both in response the accommodative forces exerted on the capsularbag. The hinge 240 therefore permits these accommodative forces to actupon the peripheral engaging edge 216 of the power changing lens 210 toactuate the opposing surfaces 212 a, 212 b away from or towards oneanother. The squared edge 239 is provided to help fix the primary lensassembly to the capsular bag and also to reduce the likelihood ofposterior capsular opacification (PCO) from occurring.

FIG. 4B depicts an IOL device 200B that is similar in many respects withFIG. 4A with the exception that the hinge 242 disposed on the centrationmembers 224 is substantially wider so as to provide less resistance tobending, compression or both in response to the accommodative forcesexerted on the capsular bag and thus onto the distal edge 236 of thecentration member 224. It is understood that for both IOL devices 200A,200B, the hinge 240 is provided on the surface facing away from thepower changing lens 210 and therefore the distal edge 236 pivot in adirection away from the power changing lens 210 when a radiallycompressive force is applied to the distal edge 236.

FIG. 4C depicts an IOL device 200C in which the primary lens assembly230 comprises only a squared edge 239 around the periphery of the fixedlens 232. Because the primary lens assembly 230 does not include ahinge, it is expected that this IOL device 200C will be significantlymore rigid than the IOL devices 200A and 200B depicted in FIGS. 4A and4B, respectively.

FIG. 4D depicts an IOL device 200D in which is similar to the IOL device200B of FIG. 4B with the exception that the hinge 244 is now located onthe surface facing the power changing lens 210. Thus, the distal edge236 will pivot in a direction toward the power changing lens 210 when aradially compressive force is applied to the distal edge 236.

FIG. 4E depicts an IOL device 200E having a greater degree of engagementbetween the power changing lens 210 and the fixed lens assembly 230. Thepower changing lens 210 and the fixed lens assembly 230 comprisecomplementary and interlocking hooks 250, 260 disposed peripherally ofthe fluid- or gel-filled lens chamber 212 and the fixed lens 232,respectively. Unlike the IOL devices depicted in FIGS. 4A-4D, the powerchanging lens 210 and the fixed lens assembly 230 are coupled to oneanother by engagement of the interlocking hooks 250, 260.

FIG. 4F depicts an IOL device 200F in which the power changing lens 210comprises a circumferential projection 246 downwardly of the peripheralengaging edge 216 to constrain the movement of the fixed lens assembly230 within the boundary defined by the circumferential portion 246. As aresult, it is understood that the fixed lens assembly 230 has a diameterthat is less than the diameter defined by the circumferential projection246.

FIGS. 5-8 depict another embodiment of a two-part IOL device 300 inwhich the power changing lens 310 is constrained within the boundariesof the fixed lens assembly 350. As shown in FIGS. 5-6, the powerchanging lens 310 has a roughly disc-shaped outer surface and comprisesan enclosed fluid- or gel-filled lens 312, a haptic system 314 and acircumferential peripheral engaging edge 316. The power changing lens310 further comprises a plurality of circumferential holes 315 disposedperipherally of the enclosed fluid- or gel-filled lens 312. The fluid-or gel-filled lens 312 comprises two opposing surfaces which are dividedinto central regions 312 a, 312 b and peripheral regions 311 a, 311 b.In a preferred embodiment, the central regions 312 a, 312 b have agradually increasing thickness radially towards the center of the fluid-or gel-filled lens 312 from the peripheral regions 311 a, 311 b. In apreferred embodiment, the center point of the central regions 312 a, 312b has a thickness that is two times or more, preferably three times ormore, and most preferably 4 times or more than the thickness of theperipheral region 311 a, 311 b. A fluid or gel 313 is contained betweenthe opposing surfaces. In another preferred embodiment, the point ofgreatest thickness in the central region 312 a, 312 b and the point ofleast thickness in the peripheral region 311 a, 311 b is a ratio of 2:1or greater, preferably 3:1 or greater, and most preferably 4:1 orgreater. In a preferred embodiment, the thickness at the optical axis orthe center of the central region 312 a, 312 b is about 200 microns andthe thickness at the peripheral region 311 a, 311 b is about 50 microns.The increased thickness in the central region 312 a, 312 b is providedso as to prevent the opposing surfaces of the fluid- or gel-filled lens312 from buckling when it is deformed in response to accommodation.

The fixed lens assembly 350 is configured to house and receive the powerchanging lens 310. The fixed lens assembly 350 comprises a fixed lens352 centrally disposed and an internal cavity defined by the fixed lens352, the peripheral side wall 356 and a plurality of radial protrusions358 projecting inwardly from the top of the peripheral side wall 356.Circumferential grooves or hinges 354 surround the fixed lens 352 andpermit pivoting or compression of the peripheral side wall 356 radiallyinward. A plurality of circumferential holes 359 are provided about theperiphery of the fixed lens 352 to permit the flow of aqueous fluidtherethrough and into the cavity 375 (FIG. 8B) defined between the powerchanging lens 310 and the fixed lens assembly 350. The holes 359 also toreduce the material bulk and thus the delivery profile of the fixed lensassembly 350. As shown in FIG. 8B, a space 375 is defined between thepower changing lens 310 and the fixed lens assembly 350.

The implantation and assembly of the two-part IOL device 300 follows twosteps. In a first step, the fixed lens assembly 350 is inserted into thecapsular bag of the eye following capsulhorexis. The fixed lens assembly350 is centered such that the peripheral side wall 356 engages thecircumferential area of the capsular bag that is most densely connectedto the zonules and the fixed lens 352 is centered about the optical axisand is in contact with the posterior portion of the capsular bag. In asecond step, the power changing lens 310 is inserted into the capsularbag and positioned within the cavity 375 of the fixed lens assembly 350such that the peripheral engaging edge 316 is in proximity to or incontact with the inner surface 360 of the peripheral side wall 356.Thus, radial compression applied to the peripheral side wall 356 istransmitted to the peripheral engaging edge 316 of the power changinglens 310 such that the fluid- or gel-filled lens increases and decreasesin curvature to provide an accommodating response to the relaxation andcontraction of the ciliary muscles of the eye, respectively.

FIGS. 9-10 are cross-sectional views of various embodiments of thetwo-part IOL device.

FIGS. 9A and 9B are cross-sectional view of two alternate embodiments ofthe two-part IOL device 400A, 400B. In both embodiments, the two-partIOL device comprises a power changing lens 410 and a fixed lens assembly450. The power changing lens 410 comprises a fluid- or gel-filled lenschamber 412 defined by opposing surfaces and a fluid or gel 413contained therein. A haptic 414 having an engaging edge 416 is providedperipherally of the lens chamber 412. The fixed lens assembly 450comprises a centrally-disposed fixed lens 452 and a hinge 454 disposedperipherally of the lens 452. The hinge 454 is preferably disposed onthe surface of the fixed-lens assembly 450 facing the power changinglens 410 such that radial compressive forces applied to thecircumferential periphery 456 causes it to pivot towards the powerchanging lens 410 and thus transmit the radially-compressive forces ontothe engaging edge 416 of the fluid- or gel-filled lens 412 to effectuatea curvature change in the opposing sides of the fluid- or gel-filledlens chamber 412. The difference between the IOL devices 400A and 400Bis that the engaging edge 416 in 400A is in spaced relation to the innersurface 460 of the circumferential periphery 456, whereas the engagingedge 416 in 400B is in contact with the inner surface 460 of thecircumferential periphery 456 in the absence of a radially-appliedforce.

Additionally the IOL devices 400A, 400B are provided with curvedsurfaces at the points of contact between the power changing lens 410and the fixed lens assembly 450 to facilitate a sliding movement betweenthem. Thus, in a preferred embodiment, at least the circumferentialperiphery 456, the engaging edge 416 and the inner surface 460 of thecircumferential periphery 456 are curved surfaces.

FIGS. 10A and 10B depict yet another embodiment of the two-part IOLdevice 500 comprising a power changing lens 510 and a fixed lensassembly 550. The power changing lens 510 comprises a enclosed lenschamber 512 defined by two opposing sides which change in curvature inresponse to radial forces applied to the periphery 516 of the haptic514.

The two opposing surfaces are divided into central regions 512 a, 512 band peripheral regions 511 a, 511 b. In a preferred embodiment, thecentral regions 512 a, 512 b have a gradually increasing thicknessradially towards the center of the enclosed lens chamber 512 from theperipheral regions 511 a, 511 b. In a preferred embodiment, the centerpoint of the central regions 512 a, 512 b has a thickness that is twotimes or more, preferably three times or more, and most preferably 4times or more than the thickness of the peripheral region 511 a, 511 b.A fluid or gel 213 is contained between the opposing surfaces. Inanother preferred embodiment, the point of greatest thickness in thecentral region 512 a, 512 b and the point of least thickness in theperipheral region 511 a, 511 b is a ratio of 2:1 or greater, preferably3:1 or greater, and most preferably 4:1 or greater. In a preferredembodiment, the thickness at the optical axis or the center of thecentral region 512 a, 512 b is about 200 microns and the thickness atthe peripheral region 511 a, 511 b is about 50 microns. The increasedthickness in the central region 512 a, 512 b is provided so as toprevent the opposing surfaces of the enclosed lens chamber 512 frombuckling when it is deformed in response to accommodation. It isunderstood that in the various embodiments of the power lens depicted inthe figures, the opposing sides preferably has the thickness profiles asdescribed herein and depicted in FIGS. 4A-4F.

The fixed-lens assembly 550 comprises a fixed lens 552 that does notchange in shape or curvature. An internal cavity is defined by the fixedlens 552 and the circumferential side walls 560. A circumferential hinge554 provided on the fixed-lens assembly 550 peripherally of the fixedlens 552. The hinge 554 is disposed around the fixed lens 554 and thuspermits the peripheral side wall 556 to be compressed radially-inwardsin the direction of the arrows B to compress the power changing lens 510at the contacting periphery 516. This, in turn, causes the opposingsides 512 a, 512 b to curve away from one another. Once the radialforces are no longer applied, the fixed lens assembly is resilientlybiased to the expanded and unaccommodated state and the peripheral sidewall expands in the direction as indicated by the arrows A.

FIGS. 11A-11F depict various alternative embodiments of the fixed lensassemblies 600A-F that may be used in connection with any one of thefixed lens assembly described herein to form a two-part IOL device ofthe type described in FIGS. 1-3. As depicted in each of FIGS. 11A-11F,the haptics 614A-F are disposed in a symmetric matter so as to ensurecentration of the power changing lens. FIG. 11A depicts a fixed lensassembly 600A having a lens 612A surrounded by four symmetricallydisposed tabs 614A. The tabs each comprise an aperture 615A and anengaging edge 616A configured to engage the capsular bag of thepatient's eye. FIG. 11B depict a similar arrangement of four haptics614B, except that the haptics each have a rounded edge 616B and hapticpairs are pointed towards one another. FIG. 11C depict an arrangement offour haptics 614C, also having rounded edges 616C with the haptics beingpointed in the same direction.

FIG. 11D depicts a fixed lens assembly 600D comprising a lens 612D and aplurality of haptics 614D each with an aperture 615D disposedtherethrough. The haptics 614D further comprise a sizing finger 620projecting from the outer engaging edge 616D. Implantation of thetwo-part IOL device typically requires the implantation of the fixedlens assembly first. Once the fixed lens assembly is implanted andpositioned, the lens capsule walls may compress the engaging edge 616Dand displace the sizing finger 620 toward the lens 612D. The extent towhich the sizing finger 620 is displaced toward the lens 612D providesan indication as to the size of the patient's lens capsule so as topermit selection of the appropriately-sized power changing lens that isto be subsequently implanted in the patient's lens capsule.

FIG. 11E depicts yet another fixed lens assembly 600E comprising fourhaptic tabs 614E each comprising a triangular shaped aperture 615E and aperipheral engaging edge 616E. The significance of the triangular shapedaperture 615E is to reduce the risk of snagging portions of the powerchanging lens during implantation.

FIG. 11F depicts a further embodiment of the fixed lens assembly 600Fcomprising a lens 612F and three plate haptics 614F projectingtherefrom. Because the configuration of the plate haptics 614F providesfor a stiffer haptic, the fixed lens assembly 600F is preferablyundersized relative to the lens capsule.

The invention described and claimed herein is not to be limited in scopeby the specific preferred embodiments disclosed herein, as theseembodiments are intended as illustrations of several aspects of theinvention. Indeed, various modifications of the invention in addition tothose shown and described herein will become apparent to those skilledin the art from the foregoing description. Such modifications are alsointended to fall within the scope of the appended claims.

1-30. (canceled)
 31. A two-part accommodating intraocular lens (IOL)device comprising: a power changing lens comprising an anterior surface,a posterior surface, an enclosed and fluid- or gel-filled lens cavitydisposed between the anterior surface and posterior surface, and aperipheral body disposed peripherally of the enclosed lens cavity; abase assembly comprising an optic centered on an optical axis and ahaptic disposed peripherally of the optic, the haptic comprising: aninner circumferential surface engaging a circumferential edge of theperipheral body of the power changing lens; and a radially-compressibleouter circumference spaced radially outward of the inner circumferenceand configured to engage a capsular bag of a patient's eye, wherein theradially-compressible outer circumference surrounds the power changinglens and is uniformly radially compressible in response to ocularforces; wherein radial forces exerted on the outer circumference of thehaptic are transmitted radially inward to the peripheral body of thepower changing lens to cause an increase in curvature of at least one ofthe anterior and posterior surfaces of the enclosed lens cavity.
 32. Thetwo-part IOL device of claim 31, wherein the anterior and posteriorsurfaces of the power changing lens are spaced away from each other. 33.The two-part IOL device of claim 32, wherein an anterior surface of theoptic is spaced away from the posterior surface of the power changinglens.
 34. The two-part IOL device of claim 33, wherein the increase incurvature of the at least one of the anterior and posterior surfacesoccurs without contact between the optic and the posterior surface ofthe power changing lens.
 35. The two-part IOL device of claim 34,wherein the increase in curvature of the at least one of the anteriorand posterior surfaces occurs without contact between the anterior andposterior anterior surfaces of the power changing lens.
 36. The two-partIOL device of claim 33, further comprising a second cavity spacing apartthe optic and the posterior surface of the power changing lens.
 37. Thetwo-part IOL device of claim 36, wherein the enclosed lens cavity andthe second cavity are not in fluid communication with the haptic. 38.The two-part IOL device of claim 36, wherein the enclosed lens cavityand the second cavity are not in fluid communication with the baseassembly.
 39. The two-part IOL device of claim 36, further comprising aplurality of holes around a periphery of the optic, the plurality ofholes configured to permit a flow of aqueous body fluid into the secondcavity.
 40. The two-part IOL device of claim 31, wherein each of theanterior surface and posterior surface of the enclosed lens cavitycomprises a central region centered on the optical axis and a peripheralregion disposed peripherally of the central region.
 41. The two-part IOLdevice of claim 40, wherein the central region of at least one of theanterior surface and the posterior surface of the enclosed lens cavityis at least two times greater than a thickness of the peripheral regionof at least one of the anterior surface and the posterior surface of theenclosed lens cavity.
 42. The two-part IOL device of claim 40, whereinthe central region of at least one of the anterior surface and theposterior surface of the enclosed lens cavity is at least three timesgreater than a thickness of the peripheral region of at least one of theanterior surface and the posterior surface of the enclosed lens cavity.43. The two-part IOL device of claim 40, wherein the central region ofat least one of the anterior surface and the posterior surface of theenclosed lens cavity is at least four times greater than a thickness ofthe peripheral region of at least one of the anterior surface and theposterior surface of the enclosed lens cavity.
 44. The two-part IOLdevice of claim 31, wherein the base assembly further comprises aplurality of radial protrusions disposed over an anterior side of thepower changing lens's peripheral body when the power changing lens isdisposed in the base assembly.
 45. The two-part IOL device of claim 31,wherein the haptic further comprises circumferential hinges between theoptic and the radially-compressible outer circumference.
 46. Thetwo-part IOL device of claim 31, wherein the power changing lens isentirely contained within the radially-compressible outer circumferenceof the base assembly.
 47. The two-part IOL device of claim 31, whereinthe optic is disposed posteriorly of the haptic.
 48. The two-part IOLdevice of claim 31, wherein the optic is disposed posteriorly of aposterior side of the haptic.